Saw sharpener



April 1, 1952 J. MGEWAN 2,590,992

SAW SHARPENER Filed 001;. 10, 1947 2 SIIEET S'-SHEET 1 JJ i4 Il f/ y J5 O /4 4l. 7

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April 1, 195.2 J. MQEWAN' 2,590,992'

sAw SHARPENER Filed om. 1o, 1947 SHEETS-SHEET 2 Patented Apr. 1, 1952 UNITED STATESPATENT OFFICE SAW SHARPENER James McEwan, San Jose, Calif.

Application October 10, 1947, Serial No. 779,001

4 Claims.

The present invention relates to saw sharpeners and is concerned more particularly with the provision of a saw Sharpener in which the sharpening device has linear movement with respect to the teeth of the saw during the sharpening operation.

In the sharpening of saws it has long been recognized that the sharpening device should have a straight line in and out movement with respect to the tooth of the saw during the sharpening operation to obtain the desired tooth profile. ln accordance with the instant invention, this result is accomplished in a simple positive manner by means which lends itself to easy operation and economical manufacture. Also, the mounting of the saw sharpening device is carried out in conjunction with the provision of a dust chute to receive the metal dust incident to the sharpening operation.

The above and other objects of the invention are attained in a preferred embodiment of the invention as shown in the accompanying drawings, in which:

Figure 1 is a side elevational View of the new Sharpener.

Figure 2 is a fragmentary sectional view taken as indicated by the line 2-2 in Figure 3.

Figure 3 is a plan view of the Sharpener with certain parts shown in section.

Figure 4.- is a vertical sectional view of the Sharpener taken as indicated by the lines 4-4 in Figure r3, with the upper and lower portions of the view taken in diierent planes.

Figure 5 is a diagram illustrating the linkage arrangement and the method of obtaining such a linkage arrangement by lay-out.

Referring to Figure l, in general the saw sharpener includes a base portion or support structure ID on which a saw support II is mounted for supporting a saw I2 in relation to a saw sharpening device or wheel I3. The wheel I3 is carried by a mounting bracket or support element I4 which is supported in a manner later described on a dust chute I6 forming a part of the base portion I3. The drive motor I'I for the wheel I3 is also mounted on the bracket I4.

The base portion IB (Figure 1) includes a pedestal 2I from which there projects upwardly a post 22 carrying the saw support I I and the dust chute I6. The saw support or positioner II is of conventional construction and is releasably clamped on the post 22 so that the height of the saw support Il can be adjusted with reference to the type and size of saw to be sharpened. The dust chute I6 has its split mounting boss 23 clamped on the upper end of the post by means of a bolt 24 and the dust chute I6 is provided with an inclined intake end 26 which is adjacent the uppermost teeth of the saw I2 and which conforms generally to the outline of the sharpening wheel I3. The discharge end of the chute I6 has mounted thereon a conventional form of blower 2l discharging into a bag 28.

The sharpening wheel I3 (Figures l, 3 and 4) has its. support shaft 3I journalled in a boss 32 of the bracket I4, and the shaft 3I is driven through a suitable pulley and belt arrangement 33 from the motor Il. The support bracket I4 for the sharpening Wheel I3 has a floating mounting on the dust chute I6 to provide for linear in and out movement of the Wheel I3 with respect to the saw l2 under manual control of the operator utilizing the handle 34. This mounting includes a main support link 36 (Figures l, 2 and 5) which is provided with a link portion at each end joined by a connecting web 36a. The lower ends of the link portions 36 (Figure 2) have aligned pivotal mountings by means of tapered studs 3l engaging in complementary respective tapered recesses in opposite bosses 38 formed on the dust chute I6. The upper ends of the link portions 36 have similar pivotal connections 3S with upstanding.

ears 4I of the bracket I4. To counterbalance the bracket I4 with respect to the above described floating pivotal mounting, a spring 42 extends vbetween the motor end of the bracket and the pedestal 2|. Also, to provide for limited in and out movement of the wheel I3 with respect to the saw I2, the dust chute I6 carries an upstanding stud 43 (Figures 1 and 3) which passes through an apertured portion 44 of the bracket I4 and has respective upper and lower stop nuts 46 threaded thereon.

To control the pivotal movement of the bracket with respect to its supporting link and to constrain the up and down movement of the sharpening wheel I3 to a linear path, a control supporting and connecting link 41 is provided (Figures 1, 3 and 4) which is forked at each end and carries respective sets of tapered pivot screws 48 engaging respectively in a boss 49 of the bracket I4 and an upstanding boss 5l on the dust chute I6.

It will be noted that the respective links 36 and 4l extend substantially at right angles to each other so that while the wheel end of the bracket I4 is moving up and down with reference to the saw I2 about its pivot axis 39, it is also controlled in a back and forth movement by the link 41, and the relative dimensions of the parts are selected so that the resultant movement of the sharpening wheel I3 is linear. This will best be understood by reference to Figure 5 which illustrates a preferred method of determining the desired relation of the parts. In Figure 5 the vertical line 6I represents the desired linear path of movement of the sharpening device, the horizontal line 62 represents the horizontal position of the bracket, with distance between the points l-I correspcndig to the distance from the center of the sharpening wheel to the axis of the pivotal connection to the link 36, whose line is correspondingly numbered. The portion 63 of the line 62 corresponds to the link 41. To determine the relation of the parts, the points I, 2, 3 and 4 are laid out equi-distance apart along the line 6|, and the corresponding positions of the upper end of the link 36 are correspondingly numbered. The points I-I, 2 2, 3 3 and 4-13 are connected to obtain the line 62 and the line 62a, 62D and 62e. Having selected an appropriate location of the connecting link i? between the link 45 and the path of movement of the wheel, equal distances are laid out from the points l, f, etc. on the line Sl to locate the respective points 5, 6, l' and 3 on the line 62, 92a, etc. These points 5 through 8 lie on the circumference of a circle having its center at Sii which corresponds to the pivot point in the boss This graphic lay-out then determines the desired length of the link 4l, and the location of its respective pivotal connections to the bracket lli and to the dust chute i6.

From the above description it will be seen that as the operator moves the sharpen-ing wheel i3 from its normal uppermost position into engagement with the saw l2 as seen in Figure l, the combined action of the compensating llinks S6 and 47 provides for substantially linear movement of the wheel i3. In this Way, the desired proile of the saw teeth is obtained.

While I have shown and described certain preferred embodiments of the invention, it is apparent that the invention is capable or variation and modication from the forms shown so that its scope should be limited only by the scope of the claims appended hereto.

Iclaim:

1. In a saw Sharpener, a base, a saw positicner on the base, a sharpening device for engaging the teeth of a sav-J on said pcsitioner, a horizontally disposed support' bracket for said device v and mountingr means for said bracket providing for substantially straight-line movement of said sharpening device with respect to a saw on said positioner, said mounting means including a pair of spaced apart rigidly connected support links each pivoted respectively to said base and said bracket about aligned horizontal vertically spaced axes, and also including a horizontally disposed control link pivotally connected about respective parallel horizontal axes between said bracket and said base.

2. In a saw Sharpener, a base including a dust chute having an intake opening, a saw positioner on the base for supporting a saw with certain of the teeth thereof aligned with the intake opening of the dust chute, a sharpening device for engaging the teeth of a saw on said pcsitioner adjacent said intake opening, a horizontally disposed support bracket for said sharpening device, a vertically disposed support element for said sharpening device having respective spaced pivotal connections to each side of said bracket and to said dust chute, and a horizontally dis' posed control link pivotally connected between said dust chute and said bracket to provide for substantially straight-line movement of said sharpening device with respect to a saw.

3. In a saw Sharpener, a base, a saw positioner on the base, a sharpening device for engaging the teeth of a saw on said positioner, a horizontally disposed support bracket for said device, and a mounting structure for said bracket providing for substantially straight line movement of said sharpening device with respect to a saw on said positioner, said mounting structure comprising a link pivotally connected to said base and pivctally connected to said bracket about respective axes extending transversely of said bracket to provide for in and out movement of said bracket and the sharpening device thereon with respect to a saw as well as for relative endwise movement of said bracket with respect to said base, said mounting structure also including a compensating link disposed lengthwise of said bracket and pivotally connected to said base and said bracket about respective axes disposed transversely of said bracket and in parallel relation to said rst named axes.

4. In a saw Sharpener, a support structure, a saw positioner on the support structure, a sharpening device for engaging the teeth of a saw on said positioner, a support element for said device. and mounting means for said support element providing for substantially straight line movement of said sharpening device with respect to a saw on said positioner, said mounting means including a link pivotally connected to said support structure and pivotally connected to said support element about respective axes extending transversely of said support element to provide for endwise movement of said support element relative to said support structure and for movement of said support element and the sharpening devices thereon relative to a saw in said positioner, said mounting means also including a compensating link disposed substantially lengthwise of said support element and pivotally connected to said support structure and said support element about respective axes disposed in parallel relation to said rst-named axes.

JAMCES MCEVAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 410,444 Radant Sept. 3, 1389 1,227,556 Armstrong May 22, 1917 1,501,564 Liiiiander July 15, 1924 1,502,085 Armstrong July 22, 1924 1,832,878 Porter Nov. 24, 1931 2,292,595 Andrianoli Aug. 11, 1942 

